Standing desks are not a health miracle and they are not a gimmick. They are a way of changing position during the day. Here is how to decide whether you need one.
The honest case for standing
The benefit is not standing. The benefit is moving. Sitting still for eight hours is hard on your back and your circulation, and so is standing still for eight hours. A height adjustable desk lets you switch, and switching is the point.
Most people who use one well spend the majority of the day seated and stand for perhaps two or three shorter stretches. If you imagine yourself standing all day, you will not, and that is fine.
When a fixed desk is the right answer
If you are between about 5 foot 8 and 6 foot, you sit comfortably at a standard desk, and you do not have back trouble, a fixed desk is not a compromise. It is more rigid, it is cheaper, there is no motor to fail, and the money saved buys a better chair, which will do more for your comfort than a standing desk will.
When adjustable is worth it
Buy adjustable if you are noticeably shorter or taller than average, because a fixed desk will never be the right height for you. Buy adjustable if you have back or hip pain that changes through the day. Buy adjustable if two people share the desk.
What to look for
Check the height range, not just the fact that it moves. A desk that only reaches 45 inches will not be tall enough for someone over 6 foot to stand at comfortably. Check the weight capacity if you run multiple monitors. And expect an electric desk to be heavier and slower to assemble than a fixed one.
Cables
The thing nobody mentions: every cable on a moving desk needs enough slack to travel the full height, and needs to be tied to the desk rather than the wall. Sort this on the day you assemble it, not the first time something unplugs itself mid call.